There are 34 known

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s of

krypton Krypton (from 'the hidden one') is a chemical element; it has symbol (chemistry), symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace element, trace amounts in the Earth's atmosphere, atmosphere and is of ...

(₃₆Kr) with

atomic mass number The mass number (symbol ''A'', from the German word: ''Atomgewicht'', "atomic weight"), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approx ...

s from 67 to 103. Naturally occurring krypton is made of five

stable isotope Stable nuclides are Isotope, isotopes of a chemical element whose Nucleon, nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The Atomic nucleus, nuclei of such isotopes are no ...

s and one () which is slightly

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

with an extremely long half-life, plus traces of radioisotopes that are produced by

cosmic rays Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar ...

in the

atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

List of isotopes

, -id=Krypton-67 , rowspan=2, ⁶⁷Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 31 , rowspan=2, 66.98331(46)# , rowspan=2, 7.4(29) ms , β⁺? (63%) , ⁶⁷Br , rowspan=2, 3/2-# , rowspan=2, , rowspan=2, , - , 2p (37%) , ⁶⁵Se , -id=Krypton-68 , rowspan=3, ⁶⁸Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 32 , rowspan=3, 67.97249(54)# , rowspan=3, 21.6(33) ms , β⁺, p (>90%) , ⁶⁷Se , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β⁺? (<10%) , ⁶⁸Br , - , p? , ⁶⁷Br , -id=Krypton-69 , rowspan=2, ⁶⁹Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 33 , rowspan=2, 68.96550(32)# , rowspan=2, 27.9(8) ms , β⁺, p (94%) , ⁶⁸Se , rowspan=2, (5/2−) , rowspan=2, , rowspan=2, , - , β⁺ (6%) , ⁶⁹Br , -id=Krypton-70 , rowspan=2, ⁷⁰Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 34 , rowspan=2, 69.95588(22)# , rowspan=2, 45.00(14) ms , β⁺ (>98.7%) , ⁷⁰Br , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (<1.3%) , ⁶⁹Se , -id=Krypton-71 , rowspan=2, ⁷¹Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 35 , rowspan=2, 70.95027(14) , rowspan=2, 98.8(3) ms , β⁺ (97.9%) , ⁷¹Br , rowspan=2, (5/2)− , rowspan=2, , rowspan=2, , - , β⁺, p (2.1%) , ⁷⁰Se , -id=Krypton-72 , ⁷²Kr , style="text-align:right" , 36 , style="text-align:right" , 36 , 71.9420924(86) , 17.16(18) s , β⁺ , ⁷²Br , 0+ , , , -id=Krypton-73 , rowspan=2, ⁷³Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 37 , rowspan=2, 72.9392892(71) , rowspan=2, 27.3(10) s , β⁺ (99.75%) , ⁷³Br , rowspan=2, (3/2)− , rowspan=2, , rowspan=2, , - , β⁺, p (0.25%) , ⁷²Se , -id=Krypton-73m , style="text-indent:1em" , ^73mKr , colspan="3" style="text-indent:2em" , 433.55(13) keV , 107(10) ns , IT , ⁷³Kr , (9/2+) , , , -id=Krypton-74 , ⁷⁴Kr , style="text-align:right" , 36 , style="text-align:right" , 38 , 73.9330840(22) , 11.50(11) min , β⁺ , ⁷⁴Br , 0+ , , , -id=Krypton-75 , ⁷⁵Kr , style="text-align:right" , 36 , style="text-align:right" , 39 , 74.9309457(87) , 4.60(7) min , β⁺ , ⁷⁵Br , 5/2+ , , , -id=Krypton-76 , ⁷⁶Kr , style="text-align:right" , 36 , style="text-align:right" , 40 , 75.9259107(43) , 14.8(1) h , β⁺ , ⁷⁶Br , 0+ , , , -id=Krypton-77 , ⁷⁷Kr , style="text-align:right" , 36 , style="text-align:right" , 41 , 76.9246700(21) , 72.6(9) min , β⁺ , ⁷⁷Br , 5/2+ , , , -id=Krypton-77m , style="text-indent:1em" , ^77mKr , colspan="3" style="text-indent:2em" , 66.50(5) keV , 118(12) ns , IT , ⁷⁷Kr , 3/2− , , , -id=Krypton-78 , ⁷⁸Kr Primordial

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

, style="text-align:right" , 36 , style="text-align:right" , 42 , 77.92036634(33) , align=center, 9.2 y , Double EC , ⁷⁸Se , 0+ , 0.00355(3) , , -id=Krypton-79 , ⁷⁹Kr , style="text-align:right" , 36 , style="text-align:right" , 43 , 78.9200829(37) , 35.04(10) h , β⁺ , ⁷⁹Br , 1/2− , , , -id=Krypton-79m , style="text-indent:1em" , ^79mKr , colspan="3" style="text-indent:2em" , 129.77(5) keV , 50(3) s , IT , ⁷⁹Kr , 7/2+ , , , -id=Krypton-80 , ⁸⁰Kr , style="text-align:right" , 36 , style="text-align:right" , 44 , 79.91637794(75) , colspan=3 align=center, Stable , 0+ , 0.02286(10) , , - , ⁸¹KrUsed to date

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

, style="text-align:right" , 36 , style="text-align:right" , 45 , 80.9165897(12) , 2.29(11)×10⁵ y , EC , ⁸¹Br , 7/2+ , , , -id=Krypton-81m , rowspan=2 style="text-indent:1em" , ^81mKr , rowspan=2 colspan="3" style="text-indent:2em" , 190.64(4) keV , rowspan=2, 13.10(3) s , IT , ⁸¹Kr , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , EC (0.0025%) , ⁸¹Br , -id=Krypton-82 , ⁸²Kr , style="text-align:right" , 36 , style="text-align:right" , 46 , 81.9134811537(59) , colspan=3 align=center, Stable , 0+ , 0.11593(31) , , -id=Krypton-83 , ⁸³Kr

Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the releas ...

, style="text-align:right" , 36 , style="text-align:right" , 47 , 82.914126516(9) , colspan=3 align=center, Stable , 9/2+ , 0.11500(19) , , -id=Krypton-83m1 , style="text-indent:1em" , ^83m1Kr , colspan="3" style="text-indent:2em" , 9.4053(8) keV , 156.8(5) ns , IT , ⁸³Kr , 7/2+ , , , -id=Krypton-83m2 , style="text-indent:1em" , ^83m2Kr , colspan="3" style="text-indent:2em" , 41.5575(7) keV , 1.830(13) h , IT , ⁸³Kr , 1/2− , , , -id=Krypton-84 , ⁸⁴Kr , style="text-align:right" , 36 , style="text-align:right" , 48 , 83.9114977271(41) , colspan=3 align=center, Stable , 0+ , 0.56987(15) , , -id=Krypton-84m , style="text-indent:1em" , ^84mKr , colspan="3" style="text-indent:2em" , 3236.07(18) keV , 1.83(4) μs , IT , ⁸⁴Kr , 8+ , , , - , ⁸⁵Kr , style="text-align:right" , 36 , style="text-align:right" , 49 , 84.9125273(21) , 10.728(7) y , β⁻ , ⁸⁵Rb , 9/2+ , , , -id=Krypton-85m1 , rowspan=2 style="text-indent:1em" , ^85m1Kr , rowspan=2 colspan="3" style="text-indent:2em" , 304.871(20) keV , rowspan=2, 4.480(8) h , β⁻ (78.8%) , ⁸⁵Rb , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , IT (21.2%) , ⁸⁵Kr , -id=Krypton-85m2 , style="text-indent:1em" , ^85m2Kr , colspan="3" style="text-indent:2em" , 1991.8(2) keV , 1.82(5) μs
, IT , ⁸⁵Kr , (17/2+) , , , - , ⁸⁶KrFormerly used to define the meter , style="text-align:right" , 36 , style="text-align:right" , 50 , 85.9106106247(40) , colspan=3 align=center,

Observationally Stable Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuc ...

Believed to decay by β⁻β⁻ to ⁸⁶Sr , 0+ , 0.17279(41) , , -id=Krypton-87 , ⁸⁷Kr , style="text-align:right" , 36 , style="text-align:right" , 51 , 86.91335476(26) , 76.3(5) min , β⁻ , ''⁸⁷Rb'' , 5/2+ , , , -id=Krypton-88 , ⁸⁸Kr , style="text-align:right" , 36 , style="text-align:right" , 52 , 87.9144479(28) , 2.825(19) h , β⁻ , ⁸⁸Rb , 0+ , , , -id=Krypton-89 , ⁸⁹Kr , style="text-align:right" , 36 , style="text-align:right" , 53 , 88.9178354(23) , 3.15(4) min , β⁻ , ⁸⁹Rb , 3/2+ , , , -id=Krypton-90 , ⁹⁰Kr , style="text-align:right" , 36 , style="text-align:right" , 54 , 89.9195279(20) , 32.32(9) s , β⁻ , ^90mRb , 0+ , , , -id=Krypton-91 , rowspan=2, ⁹¹Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 55 , rowspan=2, 90.9238063(24) , rowspan=2, 8.57(4) s , β⁻ , ⁹¹Rb , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , β⁻, n? , ⁹⁰Rb , -id=Krypton-92 , rowspan=2, ⁹²Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 56 , rowspan=2, 91.9261731(29) , rowspan=2, 1.840(8) s , β⁻ (99.97%) , ⁹²Rb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (0.0332%) , ⁹¹Rb , -id=Krypton-93 , rowspan=2, ⁹³Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 57 , rowspan=2, 92.9311472(27) , rowspan=2, 1.287(10) s , β⁻ (98.05%) , ⁹³Rb , rowspan=2, 1/2+ , rowspan=2, , rowspan=2, , - , β⁻, n (1.95%) , ⁹²Rb , -id=Krypton-94 , rowspan=2, ⁹⁴Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 58 , rowspan=2, 93.934140(13) , rowspan=2, 212(4) ms , β⁻ (98.89%) , ⁹⁴Rb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (1.11%) , ⁹³Rb , -id=Krypton-95 , rowspan=3, ⁹⁵Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 59 , rowspan=3, 94.939711(20) , rowspan=3, 114(3) ms , β⁻ (97.13%) , ⁹⁵Rb , rowspan=3, 1/2+ , rowspan=3, , rowspan=3, , - , β⁻, n (2.87%) , ⁹⁴Rb , - , β⁻, 2n? , ⁹³Rb , -id=Krypton-95m , style="text-indent:1em" , ^95mKr , colspan="3" style="text-indent:2em" , 195.5(3) keV , 1.582(22) μs
, IT , ⁹⁵Kr , (7/2+) , , , -id=Krypton-96 , rowspan=2, ⁹⁶Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 60 , rowspan=2, 95.942998(62) , rowspan=2, 80(8) ms , β⁻ (96.3%) , ⁹⁶Rb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (3.7%) , ⁹⁵Rb , -id=Krypton-97 , rowspan=3, ⁹⁷Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 61 , rowspan=3, 96.94909(14) , rowspan=3, 62.2(32) ms , β⁻ (93.3%) , ⁹⁷Rb , rowspan=3, 3/2+# , rowspan=3, , rowspan=3, , - , β⁻, n (6.7%) , ⁹⁶Rb , - , β⁻, 2n? , ⁹⁵Rb , -id=Krypton-98 , rowspan=3, ⁹⁸Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 62 , rowspan=3, 97.95264(32)# , rowspan=3, 42.8(36) ms , β⁻ (93.0%) , ⁹⁸Rb , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β⁻, n (7.0%) , ⁹⁷Rb , - , β⁻, 2n? , ⁹⁶Rb , -id=Krypton-99 , rowspan=3, ⁹⁹Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 63 , rowspan=3, 98.95878(43)# , rowspan=3, 40(11) ms , β⁻ (89%) , ⁹⁹Rb , rowspan=3, 5/2−# , rowspan=3, , rowspan=3, , - , β⁻, n (11%) , ⁹⁸Rb , - , β⁻, 2n? , ⁹⁷Rb , -id=Krypton-100 , rowspan=3, ¹⁰⁰Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 64 , rowspan=3, 99.96300(43)# , rowspan=3, 12(8) ms , β⁻ , ¹⁰⁰Rb , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β⁻, n? , ⁹⁹Rb , - , β⁻, 2n? , ⁹⁸Rb , -id=Krypton-101 , rowspan=3 , ¹⁰¹Kr , rowspan=3 , 36 , rowspan=3 , 65 , rowspan=3 , 100.96932(54)# , rowspan=3 , 9# ms
400 ns, β⁻? , ¹⁰¹Rb , rowspan=3 , 5/2+# , rowspan=3 , , rowspan=3 , , - , β⁻, n? , ¹⁰⁰Rb , - , β⁻, 2n? , ⁹⁹Rb , -id=Krypton-102 , ¹⁰²Kr , style="text-align:right" , 36 , style="text-align:right" , 66 , , , , , 0+ , , , -id=Krypton-103 , ¹⁰³Kr , style="text-align:right" , 36 , style="text-align:right" , 67 , , , , , , , * The isotopic composition refers to that in air.

Notable isotopes

Krypton-81

Krypton-81 is useful in determining how old the water beneath the ground is. Radioactive krypton-81 is the product of spallation reactions with

cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...

s striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton

s. Krypton-81 has a

half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

of about 229,000 years. Krypton-81 is used for dating ancient (50,000- to 800,000-year-old)

and to determine their

residence time The residence time of a fluid parcel is the total time that the parcel has spent inside a control volume (e.g.: a chemical reactor, a lake, a human body). The residence time of a set of parcels is quantified in terms of the frequency distribu ...

in deep

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

s. One of the main technical limitations of the method is that it requires the sampling of very large volumes of water: several hundred liters or a few cubic meters of water. This is particularly challenging for dating pore water in deep

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

aquitard An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

s with very low

hydraulic conductivity In science and engineering, hydraulic conductivity (, in SI units of meters per second), is a property of porous materials, soils and Rock (geology), rocks, that describes the ease with which a fluid (usually water) can move through the porosity, ...

Krypton-85

Krypton-85 has a half-life of about 10.75 years. This isotope is produced by the

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

and

plutonium Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...

nuclear weapons testing Nuclear weapons tests are experiments carried out to determine the performance of nuclear weapons and the effects of Nuclear explosion, their explosion. Nuclear testing is a sensitive political issue. Governments have often performed tests to si ...

and in

nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...

s, as well as by cosmic rays. An important goal of the Limited Nuclear Test Ban Treaty of 1963 was to eliminate the release of such radioisotopes into the atmosphere, and since 1963 much of that krypton-85 has had time to decay. However, it is almost inevitable that krypton-85 is released during the reprocessing of

fuel rod Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other nuclear devices to generate energy. Oxide fuel For fission reactors, the fuel (typically based on uranium) is usually based o ...

s from nuclear reactors.

Atmospheric concentration

The atmospheric concentration of krypton-85 around the

North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...

is about 30 percent higher than that at the

Amundsen–Scott South Pole Station The Amundsen–Scott South Pole Station is a science and technology in the United States, United States scientific research station at the South Pole of the Earth. It is the List of extreme points of the United States, southernmost point under ...

because nearly all of the world's nuclear reactors and all of its major nuclear reprocessing plants are located in the

northern hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

, and also well-north of the

equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

. To be more specific, those

nuclear reprocessing Nuclear reprocessing is the chemical separation of fission products and actinides from spent nuclear fuel. Originally, reprocessing was used solely to extract plutonium for producing nuclear weapons. With commercialization of nuclear power, the ...

plants with significant capacities are located in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, the

French Republic France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, the

Russian Federation Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

Mainland China "Mainland China", also referred to as "the Chinese mainland", is a Geopolitics, geopolitical term defined as the territory under direct administration of the People's Republic of China (PRC) in the aftermath of the Chinese Civil War. In addit ...

(PRC),

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

, and

Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...

Krypton-86

Krypton-86 was formerly used to define the meter from 1960 until 1983, when the definition of the meter was based on the wavelength of the 606 nm (orange) spectral line of a krypton-86 atom.

References

Sources

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** **

External links

Brookhaven National Laboratory: Krypton-101 information
{{Navbox element isotopes Krypton

Krypton Krypton (from 'the hidden one') is a chemical element; it has symbol (chemistry), symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace element, trace amounts in the Earth's atmosphere, atmosphere and is of ...

List of isotopes

Notable isotopes

Krypton-81

Krypton-85

Atmospheric concentration

Krypton-86

See also

References

Sources

External links